Mercedes driver Valtteri Bottas believes the team need more from their aerodynamic upgrade to match the pace of Ferrari.
Following a low-key start to testing, the Silver Arrows introduced an extensive new aero package for the start of this week’s second test.
The Ferrari’s have demonstrated a strong package throughout testing, with the majority of the paddock seeing them as the team to beat.
Speaking to Motorsport.com, Bottas said: “It is better. But if it’s enough, that is the big question mark.
“I definitely feel improvements since last week with the stability of the car, and with the overall downforce of the car.
“But we definitely feel that we haven’t unlocked everything that there is to unlock.
“We do still need to make improvements for sure but at least we have some time after testing to again learn more for Australia.”
The Scuderia haven’t proven to be bulletproof though, with a wheel rim issue triggering a huge crash for Sebastian Vettel on Wednesday.
But despite that setback, Bottas’ opinion on the threat they pose remains unchanged.
“They still seem strong. Obviously as always from testing to Melbourne, a lot of things can change but they do have a strong package,” he explained.
“I still think we do need to unlock more from the new package to be able to really compete with them properly.”
Mercedes’ biggest issue in the first week was finding a balance on the car for the full lap, but Bottas said the update has proven successful at tackling the problem.
“From last week to this week, definitely we have been able to improve the overall balance of the car, and the differences in the balance we had through the speed range,” he told Motorsport.com.
“We’ve been able to improve overall grip, downforce, and stability. But all those areas, we can still do better.
“It’s not the perfect car yet. Definitely we feel the potential is there. Maybe it’s another car that has quite a small sweet spot, but once you hit it it can be very quick.
“We are learning massively every day, I feel like it’s been a good step, every time I get back in the car it gets better.
“I hope I can feel that again this afternoon and tomorrow and hopefully for a bigger step in Melbourne.”